Single-Shot Version of FLAIR Sequence in the Detection of Intraventricular Anomalies: Preliminary Experience in Fetal MR Imaging Giorgia Falanga, MD,* Marco Moscatelli, MD,† Giana Izzo, MD,‡ Cecilia Parazzini, MD,‡ Chiara Doneda, MD,‡ and Andrea Righini, MD‡ Objective: To evaluate single-shot (ss) FLAIR sequence in the detection of intraventricular anomalies in a series of fetuses showing mild–moderate ventriculomegaly at ultrasound. Subjects and Methods: Fetuses with mild–moderate isolated ventriculomegaly, which underwent MR imaging between 2003 and 2014 were considered eligible. Fetuses were examined by standard MR protocol and ss-FLAIR sequence, tailored for snapshot imaging. Two paediatric neu- roradiologists evaluated MR images. Results: 542 cases were selected. MR imaging was performed at mean 26 weeks of gestation. ss-FLAIR sequence detected intraventricular findings, consistent with cysts in 10 cases. In 3/10 intraventricular cysts were also evident on ss-FSE T2 and FSE T1-weighted images. In no case diffusion weighted imaging was able to detect cyst. No cyst was highlighted on ss-FSE-T2 and FSE-T1-weighted images, without being visible also on ss-FLAIR. Conclusion: ss-FLAIR sequence may be useful to detect intraventricular anomalies especially when fetal position or maternal obesity prevents ade- quate visualization by ultrasound. Key Words: fetal MRI, FLAIR, intraventricular cyst, ventriculomegaly (J Comput Assist Tomogr 2017;00: 00–00) P renatal magnetic resonance (MR) imaging of fetal brain is to- day considered a standard of care once expert ultrasound (US) results are unclear or they rise additional suspects. 1 Since its introduction, motion insensitive snapshot imaging through T2-weighted single-shot (ss) half Fourier fast spin-echo (FSE) se- quence represents the mainstay for fetal brain MR examination, because it generates good quality and high-contrast images, even in the presence of fetal and maternal motion. 2 However, in the last decade other sequences have been added to fetal MR imaging ar- mamentarium: i.e. gradient echo (GRE)-T1 or FSE-T1-weighting, Echo-Planar (EPI) diffusion-weighted images (DWI), and GRE- EPI T2*-weighted images. These sequences expand the diagnos- tic capability of fetal MR imaging in conditions where traditional ss-FSE T2-weighted images present limitations. For example T1- weighted images are useful for detection of hemorrhages, calcifi- cations, fat depositions or to assess myelination near term, 3 while EPI-DW images allow the diagnosis of acute ischemic lesions. 4 However, these sequences have significant limitations too, such as susceptibility to motion artifacts and intrinsic low tissue-contrast resolution for FSE-T1 and GRE-T1-weighted imaging respectively. Despite the technical improvement, fetal MR imaging is still far from reaching the diagnostic accuracy of post-natal one. Avail- ability of additional complementary sequences to be used in com- bination is therefore desirable. The detection of intraventricular anomalies has proven to be affected by substantial limitations, as T1-weighting suffers from the above mentioned problems and DWI cannot distinguish be- tween normal cerebral spinal fluid (CSF) and fluid containing lesions as choroid plexus cysts. The latter are conversely easily de- tectable by prenatal US. 5 In post-natal neuroimaging, fluid attenuated inversion recov- ery (FLAIR) sequence is well known to ease the detection of high T2-weighted signal anomalies at parenchyma/CSF interface. We retrospectively assessed the capability of a single-shot ver- sion of FLAIR sequence, tailored for snapshot fetal brain imaging, in the detection of possible intraventricular anomalies in a consecutive series of fetuses showing isolated mild–moderate ventriculomegaly at US, by comparing it with other routinely used sequences, including FSE-T1-weighted, ss-FSE T2-weighted, and DW imaging. MATERIALS AND METHODS Fetuses with uni- or bilateral mild–moderate (10–15 mm atrial width) isolated ventriculomegaly detected by US examination, which underwent MR examination for clinical purposes, including ss- FLAIR imaging, in the period between May 2003 and September 2014 were considered eligible for the study. All mothers signed the specific consent form in use at our Institution for both clinical and research fetal MR imaging, according to Institutional Review Board guidelines. MR Imaging Methods A 1.5 Tesla scanner (Achieva-Dual, Philips Healthcare, Eindhoven, The Netherlands) was used for fetal MR imaging; in all cases, the mother was examined in a supine position, “feet first, ” with a phased array abdominal coil. After a scout scan to localize the fetal head, T2-weighted ss-FSE multiplanar sections (3–4 mm slice thickness, TR/TE 3000/180 ms,1.1 mm 2 in plane resolution), T1-weighted FSE multiplanar images during maternal apnoea (5.5 mm slice thick- ness, TR/TE = 300/14 ms, turbo factor = 3, 1.4 mm 2 in plane res- olution), and 3-axes DWI during maternal apnoea (5.5 mm slice thickness, TR/TE = 1000/90 ms, b-factor = 0–600 s/mm 2 , FOV = 320 Â 320 mm, matrix = 128 Â 128) were acquired. ss-FLAIR was performed with the following parameters: 4.0 mm thickness, FOV 270 Â 270 mm, 1.25 mm 2 in plane resolu- tion, 9 slices, TR 6000, TE 54, TI 2000 ms, turbo factor 63, NEX 1, acq. time 12 s, without maternal apnoea. Two senior paediatric neuroradiologists (A.R., C.P.), with more than 10 years experience in fetal MR imaging, evaluated From the *Department of Radiology, S. Elia Hospital, Caltanissetta, Italy, †Università degli Studi di Milano, Postgraduation School in Radiodiagnostics, Milan, Italy; and ‡Department of Pediatric Radiology and Neuroradiology, Chil- dren’s Hospital V. Buzzi, Milan, Italy. Received for publication June 30, 2017; accepted October 24, 2017. Correspondence to: Marco Moscatelli, MD, Università degli Studi di Milano, Postgraduation School in Radiodiagnostics, Milan, Italy (e‐mail: marco.moscatelli@unimi.it). For this work authors did not receive any funding. The authors declare no conflict of interest. Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/RCT.0000000000000701 ORIGINAL ARTICLE J Comput Assist Tomogr • Volume 00, Number 00, Month 2017 www.jcat.org 1 Copyright © 2017 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. This paper can be cited using the date of access and the unique DOI number which can be found in the footnotes.